Topic List Previews

OK updates to the main plugin to support the new Discourse Thumbnails.

Basically this involves stripping out the code TLP had built to create and manage thumbnails and add new interfaces to work with core thumbnails.

This is a rather large update, but benefits heavily from my work on the TC version:

Because Discourse presently only generates Thumbnails from within Theme Components, you must also add this very simple Theme Component to initiate the thumbnail creation: @David would be great to have a plugin only option here

NB I’m not sure how long the full plugin version will stick around. I’m likely to focus on the Theme Component and the Plugin Sidecar going forward

Please test this out in staging before committing to Production if you can. I have tested it in Production but your mileage may vary. And of course let me know of any issues …


I get this error when installing the generator component

Import Error: about.json does not exist, or is invalid


Let me revert. Thanks for testing.

UPDATE: Apologies! That’s fixed and tested in Production, please update it and refresh your browser.

Moral of the story: don’t release things late in evening when tired! (I had somehow forgotten to push the very file that was critical for it to work!). The readme wasn’t going to get anyone anywhere fast!


OK I’d better summarise the current status as things are getting confusing:

There are now two distinct setups:

  1. Existing, standard, Plugin based one. I’m thinking of replacing it with 2 though (I will give notice).
  • Plugin


  1. TC based, experimental, expect minor issues but added bonuses of Featured Images on mobile and responsiveness to sidebars … optional plugin sidecar that adds features
  • Theme Component

  • Add the sidecar plugin if you want more features: - git clone -b "theme_sidecar". This adds ‘actions’ (bookmarking and liking from Topic List) and the Thumbnail Picker in the Topic Meta Editor.

Sorry for any confusion on different setups


The component is live now and it works really well, thanks again!

The only challenge we have now is that "topic list thumbnail resolution level’ affects the featured images as well. So we have either featured images that are a bit too small or thumbnails in the topic list that are too large. Would it be possible to have a “topic list featured images resolution level”?

Edit: And another thing: Apparently, the Topic list preview plugin sorted the featured images by tagging date which makes a lot sense imho. The theme component sorts by last post date which makes the featured images change quite rapidly. Would it be possible to sort by tagging date? Thanks so much!


Good suggestion, that’s implemented: FEATURE: offer independent Featured Images resolution level · merefield/discourse-topic-list-previews-theme@0b90138 · GitHub

Please update and let me know how you get on.


Works like a charm, thanks so much! :slight_smile:

Would it be also possible to sort the featured images by tagging date (see above)?

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The plugin has it’s own API changes, unfortunately the TC does not, so not unless I can pull that from a simple existing HTTP request in one go.

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Would the publication date work? Since we do a magazine with discourse and your TC, it would be odd, if a user could change the headlines by writing a comment. :wink:

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Or can you get that feed “/tag/{tag}.json?ascending=false&order=created”?


And the plan is to continue moving forward primarily with the TC, correct?

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Yep that could work. And perhaps a setting for latest versus created


Yes correct. For all the reasons outlined earlier.

I don’t envisage needing to drop support for the plugin imminently but the TC will have the focus for new features.

The recent changes in Discourse are slightly unprecedented so hopefully we can look forward to a bit more stability in the coming months.


2. TC based, experimental, expect minor issues but added bonuses of Featured Images on mobile and responsiveness to sidebars … optional plugin sidecar that adds features

  • Theme Component
  • Add the sidecar plugin if you want more features: - git clone -b "theme_sidecar" . At this point this is functionally very very similar to plugin.

I followed these steps.

the like button does not appear. How can I show the like button ?


I’ve yet to implement that in this configuration. It’s coming :wink:


I have updated to latest version of the plugin (4.3.1) and discourse (2.5.0.beta4) and noticed that almost all of my topic list previews are gone :frowning:

I am able to regenerate the preview image on a per-topic basis, however this is a) time-consuming, and b) nudges the topics to the top after I update them.

Is there a way to automatically regenerate the topic thumbnails?

I really love this plugin - it’s done wonders for our forum and makes it look great. I also tried the [edit - it was a from a different author so not relevant to this discussion] TC but found it looks quite different and has less options - so this plugin still seems superior to me unless someone can correct me?

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Yep, a post rebake from the console will do it: Rebake all posts?

But before you do that make sure this is big:

Otherwise those posts won’t have their remote images brought into the forum and the thumbnails won’t then be created.

The Theme Component is work in progress and you need the ‘plugin sidecar’ installed for the complete feature set. Actions is not yet supported but will be soon when I get a moment.

Oh, how so? There is a slight approximation made on tile size, but apart from missing actions it should be identical (aside from the tiles ships with slight drop shadows on the TC which I prefer personally).


This worked perfectly, my thumbnails are rebuilt — thanks so much for the pointer!


Hey, similar issue as Ian C ; since the upgrade to Discourse 2.5.0.beta4, with Topic List Previews 4.4.0, most of the thumbnails disappeared (on a side-node, why not all?)



I’ve tried to rebake all posts. It did not help.

Any solution, please?

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Max days old is way too low. As I pointed out it should be a high number. 30 means anything older than a month will not be thumbnailed.

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